Galaxiesโ Align โSpin with Cosmic Filaments, Challenging Formation Theories
CAPE TOWN, SOUTHโ AFRICA – December 6, 2023 โค- In aโ revelation reshaping understanding of galaxy formation, โคastronomers have found that โฃgalaxies within a vastโ cosmic filament are rotating in alignment with the filament’s own rotation, a phenomenon likened โto tops spinning โwith their base. The research, โขpublished December 4 in Monthly โฃNoticesโ of theโข Royal Astronomical Society, suggests a dominant influence of cosmic structure on galactic spin,โ challengingโค existing models.
Theโข unprecedented finding โstems โfrom observations using the โค64 โฃantennas of the MeerKAT radio telescope in South Africa, combined โwith optical dataโข from the Dark Energy Spectroscopic Instrument (Arizona) and the Sloan Digital Skyโ Survey (New Mexico).Researchers tracked โฃthe movement of โneutral hydrogen gas within galaxies and the filaments connecting them.
“What makes this structure โunusual is not just its size, but its combination of spin alignment and rotational motion,” explained Lyla Jung of the โUniversity of Oxford. โ”It โขcan be compared to a teacup โคride at an โคamusementโฃ park. Each galaxy is like โa โขspinning cup, while the platform, the cosmic โฃfilament,โ also spins.”
Scientistsโ previously established that filaments within theโ cosmic web can rotate, based on galactic motion. However, โthe โcorrelation between filament andโ galaxy rotation directionโ is a surprise. Current theories predict galactic spin isโ often altered โคby interactions,โ collisions, andโค mergers. This new evidence indicates filament rotation may be a primary driver of how galaxies gain rotational momentum.
“These filamentsโค are a fossilโฃ record ofโข cosmic flows,” said Madalina Tudorache, also โคfrom Oxford, whoโ led the research with Jung. “This helps us understand โฃhowโ galaxies gain spin and growโ over time.”
Theโข galaxies observed are relatively young, suggesting theirโค rotations may evolve.The discovery isโฃ expected โto influenceโ galaxy evolution models and perhaps impact weak โlensing surveys used to map dark matter. The Milkyโ Way’s โrotation, for example, โis attributed โto primordial gas โคclouds fromโค 13 billion years ago.